Recess tool for trenails and dowels



Feb. 12, 194 6. E. c, SWANSON ET AL 2,394,726

RECESS TOOL FOR. TRENAILS AND DOWELS Filed July 12, 1943 .final step in Patented Feb. 12, 1946 UNITED STATES H PATENT OFFICE I 2,394,726 RECESS TOOL FOR TRENAILS AND DOWELS Edwin C. Swanson and Carl 0, R. Rudeen, Rockford, Ill., assignors to Greenlee Bros. & 00., Rockford, 111., a corporation of Illinois Application July 12, 1943, Serial No. 494,332

4 Claims.

This invention relates to a tool for imparting a desired shape to the hole adapted to :receive a trenail or dowel, and has special reference to a tool adapted to flare the walls of the opening adjacent its ends for the purpose of permitting the ends of the trenail or dowel to be expanded to lock the parts in position.

The tool herein shown and described is ;in, tended for use in the wood-working art inwhich elements of :a Wooden structureare secured together by wooden pins, dowels and thelike. This type of construction is common in the boat building art in which the pins arereferred to as trenails. According to one system now in use the trenails are so arranged that the may be expanded at their ends so as to prevent the parts from becoming dislodged even where the glue holding .the parts together has completely disintegrated, and an important .object of this invention is the provision of a simple tool for recessing i or flaring the ends of the bore in which the trenail is placed to provide space in the bore for the expansion of the trenail.

A further object of the invention is the provlsion of a tool adapted to flare the bore simultaneously at both ends thereof in a single operation of the tool.

A still further object of the invention is the provision of a recessing tool in which the cutter is normally retained wholly within the confines of a cylinder defined by the outer walls of the holder and is projected outwardly "in response to pressure applied to the holder so that the cutter is progressively forced outwardly as the tool is rotated to cut an annular recess adjacent the end of the hole Other objects and advantages will appear from the following description and the accompanying drawing, in which Figure 1 is a side elevation partly in section showing the tool disposed in a'bore of a work piece;

Fig. 2 is a fragmentar view showing partially in section the arrangement of the parts at the lower end of the tool prior to projection .of the cutter;

Fig. 3 is a view similar to Fi 2 showing the position of the parts when the cutter is projected;

Fig. 4 is a side elevation of the tool showing an intermediate step in the flaring of both ends of the bore;

Fig. .5 is a view similar to Fig. 4 showing the the flaringof the two ends ofthe bore;

Fig, 6 is a front elevation of the lower end of the cutter holder;

Fig. 7 is a front elevation of the lower cutter;

Fig. 8 is a lower end View of the lower cutter, and

Figs. 9 through 11 are sectional views showing the manner in which the trenail is disposed in the work piece.

One method now being used for making dowel connections between elements of wooden structures is shown in Figs. :9 through 11. In Fig. 9 the letter A designates a wooden structural element attached to the surface of an element 13 by means of a trenail C. This trenail consists of a dowel in which an annular groove D is pl ced in the end of the dowel. This is inserted into a bore E which is flared as shown at F adjacent its bottom, a tapered tubular wed e G being positioned with its narrowest edge barely inserted in the groove D. Thereafter the parts are forced together forcing the wedge into the position shown in Fig. 9 and thus flaring or expandin the inner end of the dowel so that it can be no longer removed from the bore. In Fig. 11 two elements of wood H and J are fastened by a trenail K having ends L and ,M expanded in the manner shown in detail in Fig. 9. The present invention is directed to a tool adapted for insertion in a previously bored hole for the purpose of recessing or flaring the bore to permit the .expension of the ends of th trenail as shown at F, L and Min Figs. 9 through 11. a

The present embodiment of the invention contemplates the provision of a shank designated generally by the numeral 1 5 adapted for reception in the chuck of a power driven tool such as a drill press or the chuck of a drill stock, as the .case may :be. Integral with the shank I5 is a shaft 16 of suitable length dependingupon the nature of the particular work, the lower end of the shaft 16 having a cutter support I! preferably cylindrical in shape and integral with the shaft. The lower end of the cutter support is beveled off diagonally as shown at l8 and is provided with :alongitudinalslot l9, opposite sides of which are provided with grooves or ways 21 and 22 parallel with the beveled and i8 as best shown in Figs. 2 and 6. The cuttersupport also has a longitudinal bore 23 opening into the slot LB within which is received a sliding plug 24 normally urged outward by means of a coil spring 25.

V Disposed within the slot 19 is a bottom cutter indicated generally by the numeral .25, the cutter having a. cylindrical lower end portion .21, a flatend suriace 21a and a laterally disposed cut- 7 i4: 7' 2,394,726 l? r itinglip or edge 28 extending from the bottom upwardly as shownbest in Figs. 2 and 3. The

cutter has spaced cam shoulders 29 and 3| on opposite sides thereof adapted to abut against the sloping lower end l8 of the holder and disposed at an angle corresponding to that of the beveled end I 8, the opposed sides of the cutter above the shoulders 29 and 3|, being flat and disposed in parallel planes for snug reception between the side walls of the slot I9, these surfaces being indicated by the numerals 32 and 33. Disposed on the surface 32 and 33 are ribs 34 and adapted for reception ofa finger 31 integral with The collar has a flange 44 provided with a cutting edge 45, the flange and cutting edge having the slope required to provide the necessary flare at the end of the hole. In service the cutter 4| is adjusted on the shaft It in such relationship with the lower cutter 26 that when the tool is forced down into the .bore, the two recesses will be produced simultaneously as shown in Figs; 4

a and 5, the cutting edge 4| .firstengaging the outer 2 moves into the work and thereafter continuing the sliding plug 24. It will be seen that when the e a plug 24 is moved upward the cutter may be slid diagonally into the slot IS with the surfaces 32 and 33 fitting snugly against the walls of the slot and the ribs 34 and 35 disposed in the ways}! and '22 in the manner shown in Figs. 2 and 3. The finger 3] then seats in the recess'36. The

' length of the cutter i preferably slightly greater thanrthe maximumlength of the slot I9 but'the spring'25 urges the plug 24 against the cutter and normally moves the. cutter downward and laterally into the position shown in Fig. 2, the

3 extent of this movement being limited by contact 1 of the finger 31 with the end of the recess 36 'as shown at 38 forming a stop for this move- 7 This causes the lower end of the cutter to project out beyond the end' of the f holder. The dimension of the cutter parallel to thefaces 32 and 33 is somewhat smaller than ment of the cutter.

the diameter of the holder and the cutter edge its cutting stroke until the parts reach the position shown in Fig. 5.

It will be seen .that the tool provides a novel means by which in a single operation the bottom of a trenail bore may b flared for the expansion of the trenail as it is inserted into the work, and likewise provides means in which both of the flares can be produced in a single unitary operation. The cutter holder I! is'made of such size as t'o's'nugly fit the bore and consequently the bore serves as a guide for the tool to insert the recess'being produced uniformly about the axis of the bore. Furthermore, the tool is so arranged that in each instance the recess is cut to a definite and prescribed depth in the work so as to cause the trenail when inserted and expanded to snugly fit the recessed bore. r I a We claim: 1

1. A recessing' tool fortrenails and the like comprising a cutterholder shaped for reception in a bore of a work piece in guidingrelation therewith and having a transverse slot in one end thereof, a cutter disposed in said slot of smaller transverse dimensions-than said holder, said outter projecting from the end of the holder and 28 projects out from the faceof the cutter a dis- 1 tance equal to the amount 'of flare or recess desired in the bottom or the work piece opening which in turn corresponds to the flareto be placed I on'the trenail. Thus it will be seen that when the shank t5, the shaft l6 and the holder IT are forced downwardly so thatthe lower end of the cutter is forced against the bottom of the opening as shown'in Fig. 2 .and with the tool rotate,

ing, the tool is forced on 'down from the position shown in Fig. 2, the cutter is forced radially outward by in teraction of'the ribs 34 and 3*,and the ways 2| and 22, bringing the cutter edge 28 the'other stop for the cutter, the parts'then assuming the position shown in Fig. 3. When the tool is withdrawn from the bore, the spring 25 havinga radially disposed cutting edge on one side thereof in sloping relation with the longitudinal axis of the tool, cooperative ribs and ways disposed betweenopposite sides of said cutter j andthe walls of said slot'inclined withrespect toithe longitudinal axis of. said holder and cutter,

said ribs and ways being positioned and shaped for movement of the'cutter with respect to the holderbetween a zlower position in which the cutter projects-from theend of saldholder and 'urgethesame to said-lower position, the cutter having lateral movementwith respect thereto, a

shaft on the opposite end ofv said holder for rotating the tool and for pressing the same against J the bottom of. the bore to move the cutter laterally outwardly with respect to'the bore and thereby cut an'annular recess at the bottom of the bore and stop means for limiting the extent of the lat- I eral movement in eachdirectiont i together'with the sloping edge of thecutting edge a 28 act to-move the cutter back within the confines of a cylinder formed by the outer walls 'of' the holder, or in other words, into the position For certain types of dowel connections it is posconnection shown in Figs. 4, 5 and :11.

prises a collar 42 disposedto fit snugly on the r shown in Fig. 2 so that the tool may be withdrawn 1 from the bore. 7 a I shaft IS in such manneras'to be capable of ad- 1 justment longitudinally with respect to the shaft,

5 the collar having a set screw 43 for the purpose of, definitely locating the cutter on the shaft.

2. A reces'sing tool for trenails and the like comprisingja cutter holder of cylindrical shape for reception into the bore of a workpiece in guiding relationship therewith, said holder having a transverse slot in the lower end thereof providing abottorn wall and spaced parallel side walls, a cutterofsmallertragnsverse dimensions than said holder disposed in saidslot said cuta ter having a substantially flat bottom end and a slopingradially disposed cutting edge ,on one side 7 thereofi cooperative ribs and ways-disposed between, said cutter and said side: walls inclined with respect to the longitudinaliaxis ofsaid holder and. positionedand shaped for movement of'the cutter on the holder between a lowerjpositionlin which said cutter projects from the end 'of said holder and an upper position'in which said outting edge projects from the side of said holder, a spring pressed sliding plunger disposed in said holder at the bottom of said slot bearing against the upper end of said cutter to normally urge the same to said lower position, said cutter having stops positioned to engage said plunger to define said upper and lower positions, and a shaft on said holder adapted for reception in a chuck for rotating the tool and moving the same longitudinally into the bore and against the bottom thereof to move the cutter to said upper position and thereby cut an annular recess at the bottom of the bore.

3. A recessing tool for trenails and the like comprising a cutter holder of cylindrical shape for snug reception into the bore of a work piece in guiding relationship therewith, said holder having a lower end inclined with respect to the longitudina1 centerline thereof and a transverse slot bisecting said inclined lower end and extending longitudinally of the holder to provide spaced parallel side walls and spaced inclined end segments on the holder, a cutter of smaller transverse dimensions than said holder supported in the lower end of the latter and in one position projecting therefrom with all parts thereof dis- I posed within a plane defined by the outer surface of the holder, the cutter having a peripherally disposed cutting edge, a substantially flat end surfac for abutment against the bottom of the bore and an opposite end spaced from the bottom of said slot in the aforesaid position, a lower end portion approaching the cylindrical in shape, and an upper portion of lesser thickness than the diameter of said lower portion having parallel side surfaces for snug reception in said slot, the junc- 'tion between said portions comprising inclined cam shoulders complemental to said end segments, cooperative ribs and ways disposed between said side surfaces and said side walls, inclined with respect to the longitudinal axis of said holder and cooperative with said end segments and said cam shoulders to move the cutter diagonally toward a second position when the holder is forced the bottom of the bore to cause the cutting edge to project from the plane of the holder and to cause said opposite end to approach the bottom of said slot, and spring means disposed within the holder acting against said opposite end and moving the cutter from the second to the first position.

4. A recessing tool for trenails and the like comprising a cutter holder of cylindrical shape for snug reception into the bore of a work piece in guiding relationship therewith, said holder having a lower end inclined with respect to the longitudinal centerline thereof and a transverse slot bisecting said inclined lower end and extending longitudinally of the holder to provide spaced parallel side walls and spaced inclined end segments on the holder, a cutter of smaller transverse dimensions than said holder supported in the lower end of the latter and projecting therefrom, the cutter having a substantially flat end surface for abutment against the bottom of the bore, a lower end portion approaching the cylindrical in shape, and an upper portion of lesser thickness than the diameter of said lower portion having parallel side surfaces for snug reception in said slot, the junction between said portions comprising inclined cam shoulders complemental to said end segments, cooperative ribs and ways disposed between said side surfaces and said side walls; inclined with respect to the longitudinal axis of said holder and cooperative with said end segments and said cam shoulders to move the cutter laterally when the holder is forced down with the end surface of the cutter against the bottom of the bore, and an inclined radially disposed cutting lip on one end of and integral with said cutter, sloping upwardly and inwardly toward the longitudinal axis of the holder, the cutter having a notch in the periphery 0 thereof disposed adjacent to the cutting lip for down with the end surface of the cutter against 4 the storage of material removed by the cutting edge in the recessing operation.

EDWIN C. SWANSON. CARL O. R. RUDEEN. 

